Holder and knife blade having a tungsten carbide edge



R. A. BOWES HOLDER AND KNIFE BLADE HAVING A TUNGSTEN CARBIDE EDGE Filed Dec. 23, 1950 April 14, 1953 IN VEN TOR. J fMflfim/w M @Q ATTO RNE Y5.

Patented Apr. 14, 1953 HOLDER 'ANDiKNIFE BL'ADE'HAVING A TUNGSTEN CARBIDE EDGE Robert v A. Bowcsflhicago, 111., .assignorto' Carbide Q Saw-8a, Tool Company;Ghicag0,,.l1l., a corporationl'of Illinois Application December 23,1950; Serial'No. 202,466

, Myinvention relates."v to a "knife .bladegand more,particularly'rto: aknife 'blade'iha'vingr a zttungsten ca'rbide edge. .My "invention has parraticular utility in cutting materialssuch as asphalt :1 roofing or other abrasive compositions, siding and roofing materials. My knife-blade. is also'useful in scribing hard and abrasive materials such mas: concrete, :metals, i etc. :in; zlayoutzcorr similar 'work.

I;1t:is: an object: .of 1my invention :to: provide a knife blade having atungsten'ca'rbide edge which :ris :simple .in construction; and economical to ;:.manufacture. 'It isanotherobject of my invention g.to,provide. a carbide-edged knife blade which is '.;.useful' .for difiicultrcutting. and scribing operati ons suchiasidescribed. above. 'It is also an 'ob- ,ject of my invention: .to-design: a knife blade ;,-;structure which is. attached to or detached from ,aholder, and to provide a holder for use there with. ,Itgis a further: object. of my invention to .1 provide, a knife blade or support for a carbide edge whichis capable'of beingv formed'from'yone ';;.thin piece of metal by operations such as stampting, bending; soldering-etc.

. Another object of my invention is to provide :a carbide-edged knife blade-having a "laminated :point construction whichis adapted. to reenforce the; point and the rest of the blade-projecting outwardly from the handle. It is a still further r object vof my invention 'to adapt myfblade :struc- 'wture'so :asto provide a seat fora carbide edge :or ;tiprwithout the necessity for separate grindvir-ingor :cutting operations to prepare such seat. H Also itis an object of my invention to provide a seat, structure on my knife blade which" will; hold the carbide edge or tip firmly against bend- -'ing :or twisting or other motion which would attend toloosen. the carbide tip from the rest of '..the. blade. A still furtherobjectof my; invenation 11 to provide a, knife blade structure in;

zzwhich the reenforced"point-portion 'ismade to :cooperate with the handle so that. the blade'will be held more securelywithinthe handle;- Fur- '.1.-ther. objects and advantages:willgappearaas .the specification proceeds.

:My invention is shown in an c; fer-redfembodiment in the. accompanyingdrawing,:-in which- Fig. 1 is a perspective view-of one form-'ofimy :knife blade secured within'at: suitable holder;

Fig, 2, a .perspectiveiviewbf my knife blade showing the folded point reenforcing portion and .;:.tungsten.carbide edge; Fig. 3, a, perspectivewview s;..similar.".to Fig. 2 but. showing the other'side of my knife blade-andthe bevelededge oftthemain 4 gClaims. (CL- 30-317) blade portion; Figa, a sectional view .takenri'n elevationon line 44 of. Fig. 1- showing .the lam- Fina'ted point construction and the tungsten. carbide, edgersecured within the recess;-Fig.-.,5,. a

- view similar to Fig. 4 but showing the reenforced point 1 before, the"; installation", of the". tungsten carbide edgev and" before, the adiacentcedge, is

'beveled; Fig. 6;.a view similar to Figs; 4tand 5 -.."showing tungstenh-carbidezsedge; in; placeurand 1 showin 'thecooperation betweenthe'sho'ulder providedbygthe folded-point" with the; forward ,1 face of the handle.

As illustrated in the accompanying drawing} (0 generally designates my newjknife blade. Knife ..blade Win the embodiment shown-consists of a j flat hook-'shaped'metallic strip ll; as seen more fclearlymin Fig. 3. Strip II is" composed:- of a holder engaging tongue portion ,,l2"'havi ng a notch, or wrecess 131 in the bottom edge-thereof. Tongue I2. is; integrally formed near its forward Mend with alaterally-extending pointed portion I4.

1 Looking. primarily, at; Fig. 2,. a thinmetallic strip l5, is superposed, on pointed portion 14;:and

the forward part of tongue...portion 12. in-"the i11ustration iven. strip l5., ,is, shaped to correspond to, point. I I 4, 'and.,1the;;forward; portion of .,tongue J2 ,and integrallyformed QWith'these members by means ofufold lB. Itwi1l;be; aD-

parent, however, that stripldcanjalso bemade 3 separatelyirom hookshapedstrip Hand'then {rigidly secured thereto. by any suitable means means .of. solder [1.

such as brazing, soldering, spot welding, .etc.j..In .,the illustration given, superposed strip l5,is securedmto .strip H at its. uppermostncorner by Since strips ll .and l5;.are

v.held together by fold l6, onlya smalliamount =,,of, solder.is-required.. at I! to secure'theseflstrips ,;into a laminated point which reenforcesflthe'bn- 451; illustrative; pretireknife; blade in.

,, .As.shown,\in,the drawings, folded overlapping ,zstrip 15, ;is, out back along the rearedgeefits ,;laterallyrextendin point to provide recess .18 (for: receiving; a thin ,piece'pr; slu of tungsten gqcarbide 19 .It will, be apparent, however, that ,,,the...adjacent pointed portion I4 could-be; cut back to provide a recess which, would serve .the ;--same purpose asv recess IS. A; slug of tungsten carbide is molded froma tungsten ,carbidemold- 1 ing powder... according .to v-;c.onventio1.1alnlxcoectin-res for insertion in recess I8. I have found it preferable to mold slug I9 in the exact shape required for insertion in recess I8, and I have found it desirable to slightly taper slug II! as shown more clearly in Figs. 4 and 6. Slug I9 can be rigidly secured within the seat provided by the cooperation of members I4 and I5 by any suitable means such as brazing or soldering. I have found that a silver-braze is admirably suited to securing slug I9 within recess I8.

It will be noted that superposed strip I5 provides a shoulder 20 extending across tongue I2 at the forward end thereof, as seen more clearly in Figs. 2 and 8. Shoulder 20, as shown in Figs. 1 and 8, can be conveniently made to abut the forward face 2| of a handle or holder 22. In the illustration given, holder 22 is composed of two complementary halves 22a and 221) which are secured together by means of screw 23. Within handle 22 a lug or projection 24 is providedon handle half 22b. The purpose of lug 24 is to "engage notch I3 in the bottom edge of tongue I2 and thereby restrain blade Ill against longitudinal movement. With the structure shown, shoulder 20 abuts face 2| of handle 22 and prevents blade Ill from being rotated either upwardly or downwardly within holder 22; Thus, strip I5 not only provides a seat for tungsten carbide edge I9 but also provides a shoulder 20 which cooperates with handle 22 to' hold plate I securely therein. 7

Operation *1 have found that my knife blade can be conveniently constructed from a thin piece of metal such as cold rolled steel by die cutting a blank of the metal by stamping operation to producethe metallic shape shown in Fig. '7. v.Inthis ,way, the entire blade I9, except for the tungsten carbide edge I9, is formed in one piece and by one stamping operation. This is particularly advantageous since recess I8 is thus formed without need for a separate grinding or cutting operation and strip I is made easier to rigidly secure to point I4 and the forward portion of tongue I 2.

The die cut shape shown in Fig. 7 then folded along the dotted line as designated so as to bring strip. I5 and strip II into close juxtaposition, as shown in Fig. 5. The upper corner of strip I5.is then soldered or securedby other, suitable means to tongue I2.

A tungsten carbide slug or edge member I9, preferably slightly tapered, is then secured within recess I8, as shown in Fig. 6. This can .be conveniently done by brazing with a silver solder. If desired, the adjacent layer of point ldcan then be ground off along the broken line indicated in Fig. 6 to produce beveled edge 25, as shown in Fig. 4.

, Blade I0 is then in completed form and a handle similar to 22 can be attached thereto so that the knife blade can be used in cuttingand scribing operations. By providing the hook-shaped blade, as illustrated, with a carbide tip on the rear edge of the laterally-extending pointed portion, the assembled knife as shown in Fig. I can best be used by drawing it toward the holder across the surface to be cut or scribed. It will be noted that this method of using the assembled knife tends to rotate blade II] upwardly within handle 22. prevented by the engagement of shoulder 20 with face 2 I, as described above.

By actual use of my knife blade under extreme conditions of wear and abrasion, I have demonstrated that it stands up. remarkably. well. The

However, this motion is efiectively tungsten carbide edge I9 is held securely within recess I8 against movement in all directions, and does not tend to become loosened or disengaged from the laminated point. Also, the laminated point construction of my blade prevents it from being bent or twisted during use even though a relatively thin sheet of cold rolled steel is used to form the blade.

As I have pointed out above, my knife blade is designed for use in cutting difficult materials such as asphalt roofing and siding. It has been found that my knife blade can be used to out such difficult materials on the job and in inaccessible places such as on scaffolds. Thus, it is possible for a workman to carry out the cutting operation at the point of installation of the material without the need for electric power connections such as would be required for the conventional motor driven cutting tools.

While in the foregoing specification I have set forth one specific structure in considerable detail for the purpose of illustrating one embodiment of my invention, it will be understood that such details of structure may be varied widely by those skilled in the art without departing from the spirit of my invention.

I claim:

1. In combination with a holder having a transverse forward face, said face having a tonguereceiving recess extending inwardlytherefrom, a tungsten carbide-edged knife blade comprising a thin metallic sheet providing a holder-engaging tongue portion integrally connected near its forward edge with a pointed portion, said tongue portion being received within said holder recess and being provided with a notch within said reupon and integrally connected along one edge thereof with the forwardmost part of said tongue portion and said pointed portion to form a laminated point having two layers, one of said layers having a recess along the edge of said point, and a fiat slug of tungsten carbide rigidly secured in said last-mentioned recess to provide a cutting edge, said strip overlying only the forward part of said tongue portion and terminating at its rear in an edge providing a raised shoulder extending across said tongue portion and engaging the transverse forward face of said holder, thereby tending to prevent any rotation of said knife blade when secured within said holder during the use of the assembled knife.

2. A tungsten carbide-edged knife blade, comprising a thin metallic sheet providing a holderengaging tongue portion integrally formed near its forward end with a pointed portion, a correspondingly shaped metallic strip integrally connected along one edge thereof to the forwardmost part of said tongue portion and overlying the forward tongue portion andsaid pointed portion, thereby providing a laminated point having at least 'two layers, one of said layers having a recess 3. A tungsten carbide-edged knife blade, comprising a thin metallic sheet providing a holderengaging tongue portion integrally formed near its forward end with a laterally-extending pointed portion, a correspondingly shaped metallic strip integrally connected along one edge thereof to the forwardmost part of said tongue portion and overlying the forward tongue portion and said pointed portion, thereby providing a laminated point having at least two layers, one of said layers having a recess along the rearward edge of said point, and a flat slug of tungsten carbide rigidly secured in said recess to provide a cutting edge, said strip terminating at its rear in an edge extending transversely across the intermediate part of said tongue portion and providing a raised shoulder thereacross for engaging a transverse forward face of a holder and thereby preventing rotation of said knife blade when secured within the holder.

4. In combination with a holder having a transverse forward face, said face having a tonguereceiving recess extending inwardly therefrom, a tungsten carbide-edged knife blade comprising a thin metallic sheet providing a holder-engaging tongue portion integrally connected near its forward edge with a laterally-extending pointed portion, said tongue portion being received within said holder recess and being provided with a notch within said recess, said holder providing a projection within said recess engaging the notch in said tongue portion and cooperating therewith to restrain longitudinal movement of said knife blade, a correspondingly shaped metallic strip superimposed upon and integrally connected along one edge thereof with the forwardmost part of said tongue portion and said pointed portion to form a laminated point having two layers, one of said layers having a recess along the rearward edge of said point, and a flat slug of tungsten carbide rigidly secured in said last-mentioned recess to provide a cutting edge, said strip overlying only the forward part of said tongue portion and terminating at its rear in an edge providing a raised shoulder extending across said tongue portion and engaging the transverse forward face of said holder, thereby tending to prevent any rotation of said knife blade when secured within said holder during the use of the assembled knife.

ROBERT A. BOWES.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,124,690 Barnett Jan. 12, 1915 2,026,348 Kamps Dec. 31, 1935 2,244,053 Comstock June 3, 1941 2,335,249 Hawkins Nov. 30, 1943 

